With the development of the high-speed optical transmission system, higher requirements are placed on the FEC (Forward Error Correction, forward error correction) technology. As a type of FEC code words with gain characteristics of approaching the Shannon limit, LDPC (Low Density Parity Check, low density parity check) codes have become a coding and decoding manner widely used in the FEC technology.
When LDPC codes are adopted to implement FEC, in a first existing technology, LDPC block codes are used to resist noises in a high-speed coherent optical transmission system; in a second existing technology, time-invariant LDPC convolutional code is used as an FEC error correction manner; in a third existing technology, time-varying periodic LDPC convolutional code is used to perform FEC protection on data in a wireless LAN (Local Area Network, wireless local area network).
When developing the present invention, the inventor finds at least the following disadvantages in the prior art:
For LDPC block code used in the first existing technology, a very great code length is required to obtain a satisfactory performance, while the implementation of a very great length of LDPC block codes leads to a very high complexity. For the time-invariant LDPC convolutional code used in the second existing technology, the performance is a little weak, and the risk of the occurrence of an error floor after the correction is very high, and meanwhile, it is difficult to implement high-parallelism-degree decoding through the check matrix structure thereof and the throughput is low, which makes it inapplicable to optical transmission. In the third existing technology, LDPC convolutional code is used as block code through cut-off, the manner not only reduces the transmission efficiency but also is inapplicable to an optical transmission system, and meanwhile, it is difficult to achieve high throughput through the check matrix thereof.